Attachment plug cap



July 5, 1932. G E E 1,866,362

ATTACHMENT PLUG CAP Filed Feb. 19, 1950 Inventor George W Lieberum;

b xfl l His Attorney.

Patented July 5, 1932 UNITED STATES- PATENT OFFICE GEORGE W. LIEIBERUM, OF STRATFORD, CONNECTICUT, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. ('JOIELI'ORATION'v OF NEW YORK ATTACHMENT PLUG CAP Application filed February 19, 1930. Serial No. 429,779.

The present invention relates to detachable caps for attachment plugs, and has for its object the provision of an improved form of cap. Specifically my invention is directed to improved means for securing the contact elecuring a contact element in-place, and Fig.

3 is an exploded plan view of the cap and contact elements.

The cap or body 4 may have any suitable contour. As shown, it is cup-shaped having a well rounded upper part 5 and'a cylindrical lower part 6. In the center there is provided an opening 7 to receive the circuit wires which are attached to the contact elements. The body ,is cut away on its under side to form a cavity 8, the peripheral wall of which is defined by the part 6. The bottom wall of the cavity is flat or has flat areas perpendicular to the axis of the body to form seats 9 for the contact elements of which there are two arranged in parallel relation. In the bottom wall of the cavity isa pair of recesses 10 for each of the contacts, one vertical wall of each registering with one end of the base of a contact. For simplicity of manufacture the recesses of one contact may communicate with those of another as shown in Fig. 2, the effect being to form L-shaped recesses which are diametrically opposite. The walls of each recess are parallel to each other and to the axis of the cap so as to permit of the use of the simplest kind of molding dies.

The body of the cap is made of suitable moldable material or composition and is molded in one o eration either b a hot or cold process; T e material shou d be relatively hard and-tough, capable of being subjected to considerable compression pressure without cracking, and capable of withstanding ordinary usage without injury. As a general proposition the moldable material should be slightly softer than the metal used in making the contact elements so as to permit the edges thereof to cut into said, material during the bending operation as will appear later. As there are various moldable compositions available for the purpose further description is unnecessary.

Both contact elements are alike, each being made of a brass or equivalent punchin having a flat base 11, a member 12 extending at right angles thereto and a binding screw 13 for a circuit wire. At opposite ends of the base are prongs or t gues 14 which are slightly wider at their outer than at their inner ends, in other words, of dove-tail sha e. The said outer ends are also slightly wi er than the recesses in the base and the sides have sharp corners or cutting edges so that when bent or forced downwardly through an arc into the recesses they cut into the walls thereof and form anchors for the contact elements. The effect of the bending and cutting operation of each prong or tongue is to slightly widen the bottom part of the slot with respect to the toppart adjacent the metal base as the prong swlngs downwardly. In other words this action serves to undercut the walls and form in eifect a dove-tail recess in which the prong is firmly wedged or anchored. The sides of the prongs may be roughened or serrated to afford additional holding means. The bending of the prongs downward into the recessesexerts considerable compression pressure on the base material and particularly at or near the ends of the bases of the contact elements. On account of this the material used in molding the cap must be'of a character to withstand this pressure without cracking.

My invention has the advantage that the cap or body is molded in one piece without any screw threaded metal inserts or holes to receive screws for securing the contact elements. By doing away with retaining screws the assembly is simplified, and the trouble incident to such screws working loose is e ntirely avoided. The contact elements and their fastening means are integral and made by punch and die operations, thereby doing away with certain small parts which are always ob'ectionable in quantity production. By suita 1y shaped tools the four prongs can be forced into place by a single operation thereby resulting in a further saving in assembly.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a device of the character described, the combination of a body of insulation having shallow recesses therein with a contact element supported thereby, said element having short prongs having enlarged ends which embrace between them a portion of the body and are wedged into engagement with the side walls of said recesses.

2. In a device of the character described, the combination of a body of insulation having seats formed thereon and shallow straight-sided recesses adjacent the seats with contact elements supported on the seats, each of said elements having a pair of short bent prongs having enlarged ends which are wedged into the recesses and are held by the side walls thereof.

3. In a device of the character described,

the combination of a body of insulation hav-- ing a central opening to receive circuit wires,

a pair of seats, and recesses adjacent the seats, with a pair of contact elements each of which has a base which rests on a seat and a pair of integral prongs having enlarged ends which are wedged into the recesses and are retained by the walls thereof.

4. In a device of the character described, the combination of a body of insulation having a central opening to receive circuit wires, a air of seats, and recesses adjacent the seats, with a air of contact elements each of which has a at base which rests on a seat, a member extending perpendicular to the base, and integral prongs at the ends of the base which are of dove-tail shape and are wedged into the recesses and are retained by the walls thereof.

In witness whereof, I have hereunto set my hand .this seventeenth day of February,

GEORGE W. LIEBERUM. 

